Referring to FIG. 9, a conventional head mount lamp seat is illustrated. The prior art has a pivotal unit 81 and a retaining strip 14. A lamp 82 is fixed to a cap 91. The cap 91 is worn by people. In the prior art, the lamp 82 is only adjustable within a small range to a fourth position P4. It cannot be adjusted rightwards or leftwards or rearwards. Thereby the use of the prior art head mount lamp seat is limited.